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1993 johnson 175 carbs leaking gas bad

T

tisdale

New member
I've replaced entire carburetor all new everything ,the float bowl does not leak, the valve seats properly shutting off gas flow in bowl. When you start the motor gas leaks from the inside of carburetor but only when motor is running I have even replaced the carburetor body to no avail, still leaks badly, It is the starboard side #5 cylinder . At a complete loss. Maybe its the throttle body ?, just had power head rebuilt and it has zero hours on it because I cant stop this leak-gas build up to dangerous to take it out. Anyone Seen this problem before?
 
I have been fooled before by thinking gas was leaking from a carb, when it was really coming from the carb or fuel lines ABOVE where the problem seemed to be.
 
daselbee said:
I have been fooled before by thinking gas was leaking from a carb, when it was really coming from the carb or fuel lines ABOVE where the problem seemed to be.
Click to expand...

all fuelines are secure and do not leak. primer solenoid also new and working correctly and in the proper position
 
Is it leaking from emulsion tube in middle of carb? Was OEM kits used? Was seat replaced? Was washer installed under seat as it don't use it even through it in kits
 
It might be its hard to see with all that spitting of gas in your face , I did replace the washer all new seals o- rings etc Thats why i though the inside of carb body was cracked so i replaced carb body and it still does the same thing
 
Spitting? Describe please.

When running only you say?

Sounds like a bad reed if spitting out the front of the carb when running.
 
when i say spitting i mean its just from the vibration of the motor and in order for me to see inside the carb ,its kinda hard with glasses on and everything wet inside carb it kinda gets a little frothy looking as well. The guy that rebuilt the power head said he would check the reed s because it did use to hick up and die when i would load up on trailer.are reeds hard to replace . I,m a machinist and a master model maker so I do have some pretty good mechanical abilities, just need some knowledge about this and i really appreciate all you guys trying to set me in the right direction.-I've been working on this for several weeks now . order parts wait a week to get them and so on and so on, the next thing ya know you got 4-5 weeks tied up very frustrating. so thanks again
 
Is it "raining" out the front of the carb? Put a paper towel up to the carb throat.....not all the way against it...and not wadded up. Flat paper towel.
See if the paper towel gets rained on and wet with gas.
You gotta go deep into the engine to get to reeds. Carbs come off, throttle body comes off, etc, and all has to be re-link and synced.
But if you have a reed sticking open, it HAS to be fixed. No other way around it.

Easy job, nothing really hard, but it is a whole lot of dis-assy and assy. You might even be able to re-use all the gaskets....
 
If when you pump the fuel primer bulb up hard, the carburetor or anything else DOES NOT leak..... the carburetor IS NOT at fault... and... neither are the fuel lines etc!

You say that this leak takes place ONLY when the engine is running. This suggests that the reed plate (leaf valve) associated with that carburetor is flawed.... check into it visually! If this is the case, the piston on its down stroke would be blowing the fuel mixture out the carburetor throat.
 
well it does spit gas out the front of carb only running at idle speed. When you open it up it is not as noticeable because its sucking in so hard. I've had carbs worked on in the past from carbs spitting and hiccuping, by quote, reputable marine mechanics and problem was never solved . cost alot of money each time .I'm starting to think this problem is what caused the motor to need power head rebuilt.I ran it like this for long time because just got tired of no one fixing the problem. Thats why I decided to do it myself.You guys are good, I'm starting to see some light at the end of the tunnel after all. Also should I even try to reuse gaskets because they are 23 years old ? Does Anyone know what this might coast if I decide not to do it myself.
 
sorry first time at this stuff,I dont just sit in front of my computer ,I do check it periodically , Then I reply . I am thank full for your response Again I apologize if I did not do this properly
 
I thought you said the powerhead was rebuilt...I assumed it was recent. Not 23 years.

Which cylinder went down? Same one the carb is spitting on? If so, it will run lean on that cyl and burn it down....(maybe).
 
In post #1, you say... "gas leaks from the inside of carburetor but only when motor is running."

In post #15, you say... "it does spit gas out the front of carb only running at idle speed. When you open it up it is not as noticeable."
********************

In reading post #1, it came across to me that fuel was really flowing out the carburetor throat

In reading post #15, that scenario is a common one that indicates a lean running cylinder due to a warped gasket sealing area (carburetor to throttle body... throttle body to intake manifold), a improperly seated goofy O Ring seal between the carburetor and the intake manifold if so equipped... OR... someone installing the intermediate and slow speed air bleed orifices backwards.

Some "mechanics" are still hung up, mistakenly thinking that those orifices measure fuel when they're actually measuring air, leading them to install orifices with a larger inside diameter that actually make the lean setting worse.

The jets are imprinted on their sides as to what size they are (inside diameter). My books only go up to 1992 (I retired) and the 1992 175hp uses Intermediate Air Bleed Jet 317473, size #30 (.030)... and ... Idle Air Bleed Jet 327745, size #40 (.040).

The Slow Speed Air Bleed Jet is always the bottom of the two jets.

If you ever suspect one of these type carburetors to be running lean.... with it running and spitting back, simply stick your finger over the opening of that slow speed air bleed jet. That'll make the carburetor run richer... sort of having you act as a manual choke. If, when you do that, the engine sort of smooths out somewhat... you've found the offending carburetor.

Check with your dealership as to what size those air bleed jets on that 1993 175hp model should be.
 
it was recent like 1 month ago and yes that cylinder I think its #5 was the worst then the one above was second worst had water or rust on the plugs and low compresion
 
i replaced goofy oring 3 times it was never pinched i checked the surface of the throttle body and it was clean and straight or flat ,checked it with straight edge I replaced the orifices as well and that is what I used #30 and #40 I noticed that whoever worked on carbs last used all # 30 so i need to replace all the ones that still have the 30S in then , but as for the carb thats causing the problems it has the correct orffices. That was going to be my next question should I replace all those other orffices even though they dont leak. when i can i will do the finger trick.also my clymer service manual says i have to replace entire assy for reed valves becuase of 60degree v6? do you know if thats correct
 
??????????
1. Joe R stated the jets you are speaking of are air metering jets. True. Why would they leak gas? No gas ever gets to those jets.
Are you now saying the gas is spraying out those air bleed jets?

2. go to shop2.evinrude.com . Drill down into the website and locate your motor. Go to the "carburetor and intake manifold" section. Now look at available parts.
You will be able to answer your own question about "entire assy".

3. Throw the Clymer in the trash and get the original OMC service manual. You will be shocked at the difference. As in here: http://www.ebay.com/itm/new-1993-OM...ash=item1c6c4cb570:g:sIQAAOSwn9lXKB-e&vxp=mtr
 
If fuel is blown out of air or intermediate jet usually the reed block gasket(1 piece)is damaged or the manifold o-ring is damaged. Now the reed block gasket had a TSB issued and if its black or red it needs replaced as it deteriorates and latest/greatest is tan or brown.
 
No the gas is not coming out those air bleeds,Its coming out of the center or inside of the carburetor,and yes its like spitting a light drizzle or rain. I did go to brp recreational products and many others and they offer the components sold separately,The Clymer manual threw me off.
 
Now I know why you guys are advanced contributors,Thanks so much for your help,I really mean that . I gotta wait until weekend to disassemble. When I'm done with that I will check for all the things That have been suggested and I will post what I find or at least what I think I have found .Thanks again-This is a tremendous help
 
today i disassembled the intake manifold assy. I was uncertain as to what i would find. Luckily for me this time i think it was oblivious as to what my problem is.The first thing I noticed was that the manifold to power head gasket was way off, i mean better than an 1/8 inch, more like 1/4. and it was right at that carb on the starboard bottom carb the one thats causing me problems. Also on that carb the reed housing had one screw in it that was not put in straight causing some damage to the reed housing. I notice that you could see light through 4 out of the 8 reed openings. Im going to replace that housing and get new reeds, all the other reed assembles looked real good and clean no chips cracks seated nicely . If this doesn't fix problem I do not no what will.should i go ahead and replace all reeds or just the one thats bad or does it make a difference.Also Wanted to let you know that I purchased the omc service manual. Someone put #30 orifices in the idle air bleed spots I think i should replace with what the book calls out #40. Hopefully I can get all the parts I need. Thank you so much for you help, I will surely let everyone know how this all turns out! Thanks again -Glen
 
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